The Non-Aqueous Titration of Phenolic Compounds

Abstract

Abstract The published methods for the titration of very weak acids are reviewed and the choice of a suitable solvent, electrode system and titrant discussed. Ethylenediamine as a solvent is rejected for routine purposes because it is toxic and unpleasant in use. Dimethylformamide is a suitable solvent for phenolic substances and gives a titration curve with a step at the end point of at least 75 mV. This is nearly the bottom limit of practicability, using tetrabutylammonium hydroxide in benzene and methanol as titrant. The electrode system preferred for its reliability is a glass indicator electrode and a saturated calomel half cell, slightly modified, as reference electrode.